Access system for a cellular network

ABSTRACT

The present invention relates to a method and system for providing access to a cellular network ( 8 ), wherein a terminal device ( 1 ) is connected to an access device ( 2 ) according to access specifications of a broadband access network ( 12 ) which is not specifically designed to be used as a part of cellular network ( 8 ). The terminal device ( 1 ) indicates to the access device ( 2 ) that it wishes to be connected to the cellular network ( 8 ), and a session or call and a radio bearer is setup between the terminal device ( 1 ) and the cellular network ( 8 ). To achieve this, a service node ( 5 ) provided in the cellular network ( 8 ) requests a suitable access bearer from the access network ( 12 ) and the access device ( 2 ) sets up a corresponding access channel towards the terminal device ( 1 ). The terminal device ( 1 ) then associates the access channel to the correct radio bearer by using a corresponding identification. Thereby, service functions of the cellular network, e.g. UMTS services, can be distributed via any access network and existing broadband or high-speed access networks can be implemented in new cellular network structures. A huge capacity enhancement can thus be offered to the network operators of the cellular network without any standardization effort or license fee and at very small investment and maintenance costs.

FIELD OF THE INVENTION

The present invention relates to a method and system for providingaccess to a cellular network, such as a Universal MobileTelecommunications System (UMTS) network, via an access network which isnot designed to be used as a part of the cellular network.

BACKGROUND OF THE INVENTION

Data services of the Global System for Mobile communications (GSM) havelaunched a new era of mobile communications. The early analog cellularmodems had become unattractive to the market as they were slow andunreliable. Now the market for data is moving onwards (more bursty) andupwards (more traffic), and the standardization institutes are workingtowards higher data rates but more significantly also towards packetdata services. This will certainly broaden the appeal to end usersbecause data is routed more efficiently through the network and hence atlower costs, and also access times are reduced.

The general trend is for data applications to generate increasinglybursty data streams, this makes for inefficient use of a circuitswitched connection. Moreover, fixed networks have seen an enormousgrowth in data traffic, not at least because of the rise of Internetaccess demand, such that it is to be supposed that mobile networks willspread as technology and customer expectations move on. The current GSMswitch network is based on narrow band ISDN (Integrated Services DigitalNetwork) circuits, so that the reason for rate limitations moves fromthe access network to the core network.

The new General Packet Radio Services (GPRS) network will offeroperators the ability to charge by the packet, and support data transferacross a high speed network at up to eight times slot radio interfacecapacity. GPRS introduces two new nodes into the GMS network, a ServingGPRS Support Node (SGSN) and a Gateway GPRS Support Node (GGSN). TheSGSN keeps track of the location of the mobile terminal within itsservice area and sends and receives packets to/from the mobile terminal,passing them on or receiving them from the GGSN. The GGSN then convertsthe GSM packets into other packet protocols (e.g. IP or X.25) and sendsthem out into other networks.

Services like multislot data and GPRS are very useful in moving the basetechnologies forwards, but if the same goals can be achieved with theexisting data services, services on the current networks should beprototyped. Therefore, a standardized mobile access mechanism for fixednetwork services, focussing on increasing the effective throughput andimmunity to dropped calls and thus reducing the needed airtime should beestablished. UMTS will deliver advanced information directly to peopleand provide them with access to new and innovative services. It willoffer mobile personalized communications to the mass market regardlessof location, network or terminal used.

Cellular radio frequencies are usually owned as licensed bands by thenetwork operators. The huge licensing fees lead to rigid licensingprocedures which make it difficult to maintain a healthy andnon-discriminatory competition environment. Currently, a strictlyseparate usage of owned access resources by individual network operatorscan be observed. Hence, ownership of frequency bands or spectrum isconsidered to be a key factor of success for the operator's business.

To achieve a wide area coverage at increasing amounts of networktraffic, smaller cell sizes are required, which makes network planningmore and more difficult and leads to increased site acquisition costsand radio access network investments. Moreover, huge and rigidstandardization efforts are required to introduce new access systems.

However, given the massive investments that have been made in existingnetworks of all types, and the enormous capital value that stillattaches to most of them, operators and users will wish to continue toexploit them until the end of their useful lives. Almost all existingnetworks can be used as access networks for IP-based services.Therefore, interoperability between UMTS terminals and other IMT-2000(International Mobile Telecommunications-2000) network family members,or even non-UMTS access networks is a key requirement. In particular,UMTS operators should be able to use common access networks owned byother access network providers, while the user has subscription onlywith the UMTS operator.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a methodand system for providing access to a cellular network, by means of whichaccess facilities can be increased.

This object is achieved by a system for providing access to a cellularnetwork, the system comprising:

-   -   at least one access device for establishing a connection to a        cellular network via an access network which is not specifically        designed to be used as a part of the cellular network; and    -   a service node specifically designed to be used as a part of the        cellular network and arranged to request an access bearer from        the access network in response to a setup request received from        the at least one access device.

Furthermore, the above object is achieved by a method of providingaccess to a cellular network, the method comprising the steps of:

-   -   establishing communication means between a terminal device and        an access network which is not specifically designed to be used        as a part of the cellular network;    -   indicating by the terminal device to the access network that a        connection to said cellular network is required;    -   sending a request for connection setup from the access network        to the said cellular network;    -   establishing a data transfer means between the access network        and said cellular network;    -   indicating to the terminal device that a communication with said        cellular network is enabled and optionally modifying the data        transfer means between the terminal device and the access        network; and    -   signaling from the terminal device to said cellular network via        the established data transfer means.

Additionally, the above object is achieved by a terminal device forproviding an access to a cellular network, the terminal devicecomprising:

-   -   higher layer protocol means for providing a signaling function        to the cellular network;    -   lower layer protocol means for providing a signaling function to        an access network which is not specifically designed to be used        as a part of the cellular network; and    -   adaptation means for providing an adaptation between the lower        layer protocol means and the higher layer protocol means so as        to establish a transparent connection to the cellular network        through the access network.

Moreover, the above object is achieved by a network node for providingaccess to a cellular network, the network node comprising:

-   -   higher layer protocol means for communicating with a terminal        device via an access network which is not specifically designed        to be used as a part of the cellular network; and    -   lower layer protocol means for signaling with the non-integrated        access network to request a suitable access bearer from the        access network;    -   wherein the suitable access bearer is used to establish a        transparent connection between the terminal device and the        network node through the access network.

In addition thereto, the above object is achieved by an access devicefor providing access to a cellular network, the access devicecomprising:

-   -   higher layer protocol means specific to the cellular network,        for receiving from a terminal device a signaling indicating a        request for a connection to the cellular network; and    -   lower layer protocol means specific to an access network which        is not specifically designed to be used as a part of the        cellular network, the lower layer protocol means being arranged        to handle the setup of a connection to a service node of the        cellular network via the access network in response to the        receipt of the signaling and to setup a requested type of access        channel towards the terminal device, which has been requested by        the service node.

Throughout the present application, the term “access network which isnot specifically designed to be used as a part of the cellular network”is intended to designate any independent access network, non-integratedaccess network and/or external access network which is not specificallyadapted to be used as a part of the cellular network which is to beaccessed. This means e.g. that the access technology of the accessnetwork is not specifically designed to be used as a part of theaccessed cellular network. The access network may be based onnon-licensed technology such that it may be shared by different cellularoperators to provide access to their cellular networks. The accessnetwork may be connected to the cellular network in an add-on way, i.e.by preserving major characteristics of the access network and thecellular network, respectively, as defined by existing standards andspecifications. For example, an access network operating in anunlicensed broadband typically is different in its characteristics froma cellular network operating in a licensed band. Moreover, protocolstandards or signalings may differ in some or all protocol layers.

Accordingly, a system concept for a cellular network is provided, inwhich independent access networks can be used as alternative radioaccess facilities for the cellular network, e.g. a UMTS network.Thereby, seamless access to all services of the cellular network can beprovided over various radio access systems. As an example, a UMTS overbroadband radio system can be established, which supports seamlessaccess to all UMTS services and will deploy UMTS mobility managementprinciples.

This provides to the users of mobile terminals the advantages that avery convenient high-speed wireless system for home, office and otherhot-spot environments can be established, such that attractive publicwireless services can be provided at reasonable prices. Furthermore, thesame type of service can be used at any location, since cheap and fasthot-spot systems can be handed over to the global cellular umbrella andleaving a hot-spot.

Due to the transparent connection through the access network, theGSM/UMTS security functions can be moved to new wireless devices. Theuser can rely on secure payments and other confidential transactionsprovided by the familiar operator over the new system and thus may startto use e-commerce. Thus, any UMTS service can be provided globally viaany compatible access network.

As regards network operators, an easy way is provided to become a majorwireless Internet service provider. In particular, a huge capacityenhancement can be offered without major new technology developments orstandardization efforts and license fees, while only very smallinvestments and maintenance costs are required for the additionalservice nodes. Thereby, access costs are reduced for the networkoperators, since common access networks can be shared by differentoperators. Moreover, even different radio technologies may be used toaccess the same services, while the best radio technology may be chosenfor each environment. The operator can concentrate on the core businesswhich has the best margins and may leave the broadband access handlingto other parties. The role of the backbone service provider is therebyseparated from the role of the access provider, and more modular systemstructures can be developed with radio access systems being moreseparated from the remaining cellular infrastructures.

Additionally, a new type of business is generated for the provision ofaccess networks, which is performed by the owners of existing and futuredistribution or access networks. Additionally, the access devices becomeconsumer products rather than part of an invisible access networkinfrastructure, since the access providers have to install correspondingaccess devices for providing the transparent connection through theiraccess or distribution networks. The network terminals may be arrangedas specific terminals adapted to their point of use, or as cellular dualmode terminals which can be used in any environment.

Thus, the new access system offers on one hand operators the possibilityto extend their cellular service offering to new environments like homesor public hot-spots and on the other hand it dramatically increases theradio capacity available for future cellular services. The system can beused as a UMTS capacity enhancement and as a low cost and high bit-rateradio extension e.g. in homes or indoor or outdoor hot-spot areas whereutilization of low cost and high bit-rate services and continuousreachability from the UMTS backbone network is desired. Thereby,seamless access to all UMTS services can be provided, and the accessnetworks can be introduced as alternative or additional radio accesstechnologies for UMTS.

The connection may be established to a terminal device arranged toconnect to at least one access device according to the accessspecifications of the access network. Furthermore, terminal device maybe arranged to indicate a connection request to the at least one accessdevice by using an adaptation layer signaling of said cellular network,the adaptation layer signaling being adapted to provide a mappingfunctionality between the lower layer protocols of the access networkand the higher layer protocols of the cellular network. Then, theterminal device and the cellular network establish or re-establish asession, call or/and a radio bearer. The establishment orre-establishment of the session or call may be achieved by an SM(Session Management) or SIP (Session Initiation Protocol) signaling,while the radio bearer may be established or re-established by an RRC(radio resource control) signaling. Specifically, the higher layerprotocol functions of the terminal device may be based on UMTS protocolfunctions that operate on top of the UMTS transport channels in the UMTSprotocol architecture.

According to an advantageous embodiment, the service node is a broadbandservice node arranged to request the access bearer by initiating abearer setup procedure according to a signaling protocol specifiedbetween the access network and the cellular network. Preferably, theaccess bearer is selected from an agreed set. The terminal device isthen arranged to associate an access channel set up by the access deviceto a correct transport channel or another similar cellular networkresource of the cellular network by using a transport channel or similarcellular resource identification.

Preferably, a UDP transport means is setup between the access device andthe service node.

As regards the billing function, the at least one access device oranother network device of the access network may be arranged to monitorresource usage by an active connection between a terminal device and acellular network and to report the monitoring result to the centralizednetwork device or gateway device which is arranged to sort the resourceusage according the originating cellular network and to increase anaccess resource charging bill for the operator of the originatingcellular network according to predetermined rules agreed for the setupaccess bearer type, and to allocate a corresponding capacity for thedata transmission.

The service node may distribute a broadcast information of the cellularnetwork such as System Information or Paging messages to the gatewaydevice, and the gateway device may then distribute the systeminformation to connected access devices.

In particular, for the established communication between the terminaldevice and the cellular network via the non integrated Access Network,the service node may provide predetermined functions of the cellularnetwork, comprising radio bearer management, encryption, IP-headercompression, RLC level segmentation and/or retransmission, and MACmultiplexing. It may be split into separate user plane gateway andcontrol plane servers. Furthermore, the service node can be connected toan SGSN by a standard lu interface and/or to other service or switchingnodes by an lur signaling interface for supporting seamless interservicenode and interaccess system handovers.

The access network may be a network, e.g. a broadband radio accessnetwork, arranged separately from the communication system on which thecellular network is based. It may be used for accessing several ones ofthe cellular network, which may be a UMTS infrastructure network. Inparticular, the access network may be arranged to use Bluetooth (BT),IEEE 802.11a/b, IEEE 802.15, or BRAN HL2 based radio technology.Additionally, the access network may be arranged to be used forestablishing a connection to other types of networks which differ fromthe cellular network. It may provide alternative methods specific to theaccess network so as to realize lower layer protocol functions ofintegrated access networks specifically designed to be used as a part ofthe cellular network. Specifically, the access network may be amultipurpose access network adapted to offer transport services for thecellular network, and the cellular network may be an access independentnetwork adapted to be able to utilize transport services provided byseveral types of access networks.

The terminal device may be arranged to scan the signal strength of otheraccess devices and to perform handover by starting a normal connectionestablishment procedure towards a new access device. As regards the datatransport functions of the access system, transport channel data streamsof the cellular network may be transported on top of transport bearersbetween the access network and the cellular network and on top of thecommunication channels provided by the access technology of the accessnetwork between a terminal device and the access network. Only dedicatedtransport channels of the cellular network may be used in integratedsystem parts specifically designed to be used as a part of the cellularnetwork, when a connection is established via the access network. Then,the access network may provide a mapping function for mapping thededicated transport channel data streams of the cellular network to thecommunication channels provided by the access network.

The cellular network may provide a mapping function for mapping adesired service quality to the communication channel characteristics ofthe access network, and to use the mapped communication channelcharacteristics to request a transport service from the access networkfor a data stream to be established.

The access device may use an indicated scheduling information anddefined mapping rules between time references and its internal clock forscheduling broadcast messages of the cellular network.

According to another advantageous embodiment, an association between aparticular data stream of the cellular network between the terminaldevice and the cellular network and a particular communication channelbetween the terminal device and the access network is achieved bytransferring a binding information both directly from the cellularnetwork to the terminal device and from the cellular network via theaccess network to the terminal device upon setting up the data streamand communication channel, respectively.

A signaling specific to the cellular network may be carried out via theset up bearer transparently through the access network which is arrangedto only allocate the respective capacity. Preferably, broadcasting andpaging channels are multiplexed to one access specific channel.Furthermore, a broadcasting channel with the same address or logicallocation may be used for a group of access devices of the accessnetwork, and the terminal device may be arranged to listen to only onechannel while changing between access devices of the same group. Thebroadcast channel of the access network may be adapted to broadcastbroadcast information originating from the cellular network. Thescheduling of the broadcast information of the cellular network by theaccess network is preferably compatible to the scheduling of thebroadcast information of the cellular network by an integrated accessnetwork arranged as a part of the cellular network. The access networkmay receive from the cellular network messages to be broadcastedtogether with a scheduling information used for broadcasting. Then, thescheduling information may indicate time references of the cellularnetwork at which the broadcast message shall be sent by the accessnetwork.

The terminal device may be arranged to use its power saving featuresspecific to the cellular network when monitoring a broadcast informationof the cellular network via the access network, by determiningcompatible transmission times for pieces of broadcast information of thecellular network and by activating its receiver functions only atrequired time instances. When the connection is set up, a set of lowerlayer functions of the cellular network may be disabled and thecorresponding functions of the access network may be used instead. Anidentity utilized by the cellular network for the user of the terminaldevice and/or for the terminal device itself does not have to benotified to the access network. The terminal device may be arranged toestablish a new connection with the access network, which is notassociated to a previous connection by the access network, when theterminal device moves from the coverage or cover area of one accessdevice to the coverage or cover area of another access device of theaccess network. Furthermore, the terminal device may be arranged toinform only an identifier of the cellular network to the access network,when the terminal device contacts the access network for accessing thecellular network.

Regarding the timing function of the access system, a timing reference,e.g. SFNs, of the infrastructure of the cellular network may be mappedto specific timing references of the access network.

In the following, the present invention will be described in greaterdetail on the basis of a preferred embodiment with reference to theaccompanying drawings, in which:

FIG. 1 shows a schematic block diagram of a network configurationcomprising an access system according to the preferred embodiment,

FIG. 2 shows an interface architecture of an air interface according toa preferred embodiment,

FIG. 3 shows an interface architecture of an interface between an accesspoint and a gateway device of an access network,

FIG. 4 shows an interface architecture between an access network and aservice node of the UMTS network,

FIG. 5 shows a schematic block diagram indicating access networkaddressings and connections,

FIG. 6A shows protocol stacks of the air interface with respect to theradio access network user plane,

FIG. 6B shows protocol stacks of the air interface with respect to theUMTS Access Stratum User Plane,

FIG. 6C shows protocol stacks of the air interface with respect to theUMTS Non Access Stratum User Plane,

FIG. 7A shows protocol stacks of the air interface with respect to theradio access network control plane,

FIG. 7B shows protocol stacks of the air interface with respect to theUMTS Access Stratum Control Plane,

FIG. 7C shows protocol stacks of the air interface with respect to theUMTS Non Access Stratum Control Plane,

FIG. 8 shows a combined UMTS-HL2 radio interface protocol architecture,

FIG. 9 shows protocol stacks of the interface between the access pointand the gateway device with respect to the control plane,

FIG. 10 shows protocol stacks of the interface between the gatewaydevice and the service node with respect to the control plane,

FIG. 11 shows a signaling diagram for an initialization of the accesspoint towards the gateway device,

FIG. 12 shows a signaling diagram for the initialization of the gatewaydevice towards the service node,

FIG. 13 shows a signaling diagram for a UMTS information broadcastingover the access system according to the preferred embodiment,

FIG. 14 shows a state transition diagram of the access system accordingto the preferred embodiment,

FIG. 15 shows a signaling diagram for a network assisted statetransition from a NULL state to an IDLE state,

FIG. 16 shows a signaling diagram for a state transition from an IDLEstate to a CONNECTED state,

FIG. 17 shows a signaling diagram for a state transition from an IDLEmode to the CONNECTED mode,

FIG. 18 shows a signaling diagram for a transition from the NULL stateto the IDLE state and directly to the CONNECTED state,

FIG. 19 shows a signaling diagram for a transition from the CONNECTEDstate to the IDLE state,

FIG. 20 shows a signaling diagram for a UMTS data stream setup,

FIG. 21 shows a signaling diagram for a UMTS data stream release, and

FIG. 22 shows a signaling diagram for a handover procedure.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following, the preferred embodiment of the method and systemaccording to the present invention will be described on the basis of awireless broadband UMTS based system in which independent broadbandwireless access networks are introduced as alternative or additionalradio access technologies for UMTS. Thus, such a UMTS over broadbandradio system supports a seamless access to all UMTS services.

FIG. 1 shows a schematic diagram of the network architecture accordingto the preferred embodiment, wherein a broadband access provider network(BAN provider network) 13 is connected via an IP (Internet Protocol)network 4 to a UMTS operator network 14. The access system is usable forUMTS radio capacity enhancement in environments suitable to broadbandradio. According to FIG. 1, the access system comprises one or aplurality of UMTS backbone networks 8 operated by a UMTS operator, andone or a plurality of broadband access networks 12 (BAN networks)operated by independent access network providers. Thus, the BAN networks12 can be regarded as non-integrated or independent or external accessnetworks. The BAN network 12 may be based on a non-licensed radiotechnology and thus a common BAN can be shared between cellular networkoperators. In particular, the access system comprises a lu interface tothe UMTS backbone network 8 and a simple IP based interface I-4 to theBAN network 12 (non-integrated access network), wherein only very basicconnection establishment/release and data transport services areprovided by the interface I-4. The BAN network 12 consists of accesspoints (APs) 2 for providing a radio access by establishing aradio-connection to a mobile terminal (MT) 1. Furthermore, a controlserver or gateway device called BAN gateway (BANGW) 3 acts as adistributor and broker for control signaling between access points 2 andthe UMTS network 8. Thus, the access points 2 terminate the broadbandradio interface. The BANGW 3 is arranged to hide the internal logicalstructure of the BAN network 12 from external networks. User planeconnections are established logically directly between the access points2 and the UMTS network 8. In general, the access points 2 may correspondto any kind of access device which may comprise a general purposephysical access point and a separate physical node behind the accesspoint handling cellular connection specific functions.

The BAN network 12 is connected to a new logical UMTS network element orservice node called Broadband Service Node (BSN) 5 and added to the UMTSnetwork 8 to provide an interface functionality towards the BAN network12. The function of the BSN 5 corresponds to a Serving RNC (RadioNetwork Controller) of the UMTS network 8. However, the BSN 5 may not bearranged to manage BAN radio resources, and the conventional lubinterface is replaced by the above mentioned simple I-4 interfacetowards the BAN network 12. The functions of the BSN 5 include radiobearer management, UMTS encryption, UMTS IP header compression, UMTS RLC(Radio Link Control) level segmentation and retransmission, apossibility for UMTS MAC (Medium Access Control) multiplexing.

It is noted that, due to its non-licensed radio technology, the BANnetwork 12 may be shared by several UMTS networks.

In practice, the BSN 5 may be split into separate user plane gateway andcontrolled plane server functions. The BSN 5 is connected to an SGSN 6of a GPRS core network via a standard lu interface and may be connectedto other BSNs and RNCs by lur signaling interfaces for supportingseamless inter BSN and inter access system handovers. Furthermore, theGPRS network of the UMTS network 8 comprises a GGSN 7 which provides agateway function to the Internet 10 or other external networks 11 likee.g. corporate networks (CN) or IP-based multimedia networks (IM).Additionally, a home subscriber server (HSS) 9 is provided as asubscriber data base for storing subscriber specific information. Thefunction of the HSS 9 corresponds to the function of the home locationregister (HLR) of a circuit switched network environment.

The mobile terminal 1 is arranged to establish an access specificassociation with one of the access points 2. In particular, theestablishment of access specific connections such as BRAN DLC (BRAN DataLink Control) user connections for UMTS data streams can be triggered bythe mobile terminal 1. Furthermore, existing UMTS data streams can bemapped to access specific channels of the BAN network 12, e.g. BRAN DLCuser connections. The mobile terminal 1 may provide an operating accessspecific air interface as defined e.g. in the ETSI BRAN HL2 (HIPERLAN 2)specifications. To achieve this functions, the mobile terminal 1 maycomprise a protocol function of an operating access specific UMTSconvergence layer (UMTS CL), a UMTS C-plane functionality for operatinga simplified version of the UMTS RRC (Radio Resource Control) protocolmainly for bearer and mobility management and UMTS higher layerprotocols, such as mobility management (MM) and session management (SM).Furthermore, the mobile terminal 1 comprises a UMTS U-planefunctionality for operating UMTS PDCP (Packet Data Convergence Protocol)and RLC (Radio Link Control) protocols. Thus, the mobile terminal 1provides UMTS higher layer protocols with C-plane and U-planefunctionality and broadband radio protocols with C- and U-planefunctionalities. Thereby, control and user signalings can be provided tothe UMTS network 8 and also to the BAN network 12.

The access points 2 are arranged to broadcast system information of acellular network (e.g. the UMTS network 8) via the BAN access interfaceaccording to an adaptation layer protocol, e.g. an access specific UMTSconvergence layer, and to communicate as a client with the BANGW 3 by asignaling protocol or application. In the following, this signalingprotocol or application is called access network control protocol (ANCP)and is required to exchange signaling messages between thenon-integrated access network (e.g. the BAN network 12) and the cellularnetwork (e.g. the UMTS network 8). This signaling is related to settingup and release of connections for individual terminal devices or userequipment, setting up and release of data streams between the terminaldevices or user equipment and the UMTS network 8, as well asdistribution of broadcast information for idle mode terminal devices.This kind of protocol is run on top of a signaling means or signalingbearer which can be based on SCTP, UDP, TCP or similar transport means,or even the signaling parameter exchange can be realized by an SNMPmessage transfer as described in the present exemplary embodiment. Theadaptation layer protocol is required to provide a mapping functionalitybetween the lower protocol layers of the BAN network 12 and the higherprotocol layers of the UMTS network 8. This mapping functionality isadapted to make the BAN specific protocols look like the protocolsreplaced from the UMTS network 8 by these BAN specific protocols. Theadaptation layer protocol is terminated in the mobile terminal 1 and inthe access points 2. The functions of the adaptation layer protocolcomprise scheduling the UMTS network broadcast information over the BANaccess interface according to the scheduling information provided to theBAN network 12 by the UMTS network 8, and mapping access interface datastreams to the data streams between the BAN network 12 and the UMTSnetwork 8. In the connection and data stream setup phase this protocolis used to exchange UMTS network related information between the accesspoints 2 and the mobile terminal 1 to provide a means for a successfulestablishment of a communication or data transfer means between themobile terminal 1 and the UMTS network 8.

Furthermore, the access points 2 are arranged to map access specificchannels such as BRAN DLC user connections to BAN transport bearers ofthe BAN network 12. Additionally, the access points 2 operate accessspecific air interfaces according to the BAN network specifications andalso the adaptation layer protocol (e.g. access specific UMTSconvergence layer protocol). In addition thereto, an accounting functionfor collecting accounting information (amount of bytes, elapsed time) ofactive connections may be provided in the access points 2. Thus, theaccess points 2 provide a mapping function between radio channels andBAN transport bearers, and a security association with the BAN gateway3.

The BAN gateway 3 communicates as a client with the BSN 5 by using theANCP provided for BAN signaling link management. On the other hand, theBAN gateway 3 communicates as a server with the access points 2 by usingthe ANCP. Thus, the BAN gateway 3 is arranged to map data flows betweeninternal and external transport bearers with respect to the BAN network12. Thereby, a security association can be established between the BANgateway 3 and any access point and the BSN 5. Additionally, the BANgateway 3 can act as a signaling proxy and distributor between theaccess points 2 and the BSN 5, while the logical structure of the BANnetwork 12 is hidden from the BSN 5. The BAN gateway 3 may additionallybe arranged to provide backbone system information and a pagingdistribution function to the access points 2. The interface between theBAN gateway 3 and the access points 2 is called I-3 interface.Furthermore, the interface between the access points 2 and the mobileterminal 1 is called I-2 interface.

The BSN 5 is arranged to provide a maintenance function of the UMTSconnection with a mobile terminal by running a limited or reduced UMTSRRC protocol, and to provide a maintenance function of UMTS data flowswith the mobile terminal 1 by running UMTS PDCP and limited or reducedRLC protocols. In particular, the BSN 5 communicates as a server withthe BAN gateway 3 by using the ANCP, and communicates with the SGSN 6 byusing a signaling defined for the UMTS lu interface. Thus, the BSN 5provides a data transport function to and from the BAN network 12. Whilethe UMTS signaling is managed towards the mobile terminal 1, a securityassociation is established with the BAN gateway 3, a connection andbearer management is provided towards the BAN network 12 with the ANCP,and the usual UMTS interface is provided to the SGSN 6.

FIG. 2 shows an interface architecture of the I-2 interface between themobile terminal 1 and the access points 2. In FIG. 2, a situation isshown, where two mobile terminals 1 are connected to one of the accesspoints 2 and the BSN 5. The I-2 interface is an air interface whichconsists of two parts, a UMTS part and an access specific part. The UMTSpart is terminated in the BSN 5 and the access specific part isterminated in the respective access point 2. An access point 2 maycommunicate with one or several mobile terminals 1, while the mobileterminal 1 communicates only with one access point 2 at one time.

The access specific part of the interface I-2 complies with thebroadband radio technology lower layers, e.g. BRAN HL2 PHY (Physicallayer) and DLC or equivalent layers of BT or WLAN (Wireless Local AreaNetwork) access technologies. In the UMTS part, the higher layers aredefined for UMTS L2 (e.g. MAC, RLC, PDCP) and L3 (RRC, MM, SM), whilecertain restrictions for the usage of UMTS protocols over the accesssystems may be implemented. The UMTS specific part is transparent to theaccess points 2. The air interface I-2 and the access points 2 arearranged to transport transmission and scheduling of UMTS systeminformation broadcast messages. Thus, as can be gathered from FIG. 2, alower layer signaling may be established between the mobile terminals 1and one of the access points 2, and a higher layer signaling may beestablished between the mobile terminals 1 and the BSN 5 via the BANnetwork 12.

FIG. 3 shows an interface architecture of the I-3 interface between theaccess points 2 and the BAN gateway 3. The BAN gateway 3 is acentralized control entity in the BAN network 12. The functions of theBAN gateway 3 are more related to the transport network level than tothe radio network level. At the radio network level, the function of theBAN gateway 3 is to distribute broadcast information to correct accesspoints and to handle initialization of individual access points. The BANgateway 3 may be connected to one or several access points, while everyaccess point can be connected to only one BAN gateway 3. The I-3interface is a BAN internal interface and is based on IP transportfunctions. The access points 2 and the BAN gateway 3 communicate whicheach other by a specific application layer protocol of the access systemwhich is called ANCP, and which is defined in the ETSI 3GPPspecification TS 25.301, “Radio Interface Protocol Architecture”. TheANCP provides common procedures not specific to a particular mobileterminal and dedicated procedures specific to a particular mobileterminal. In general, the ANCP can be any signaling protocol requiredbetween an access network (e.g. the BAN network 12) and a cellularnetwork (e.g. the UMTS network 8). Then, this signaling protocol orsignaling application is run on top of a signaling bearer which might bee.g. SCTP (Stream Control Protocol), TCP or UDP, SNMP (Simple NetworkManagement Protocol) or some other suitable signaling bearer capable ofcarrying signaling messages between two networks. For common ANCPprocedures, one ANCP link is established between one of the accesspoints 2 and the BAN gateway 3. The common ANCP is used to deliver UMTSbroadcast and paging information to the access points 2. A dedicatedANCP connection is dynamically established by the access points 2 forevery mobile terminal accessing the network via a respected one of theaccess points 2. Each dedicated ANCP connection is arranged to utilizeits own signaling protocol link separated from each other by theirtransport addresses e.g. UDP (User Datagram Protocol). The dedicatedANCP connection is used to setup and release user plane transportbearers between one of the access points 2 and the BAN gateway 3.However, it is to be noted that the user plane for transporting UMTSdata streams between the access point 2 and the UMTS network is notlogically routed via the BAN gateway 3, as described in the followingwith reference to the interface I-4.

FIG. 4 shows the architecture of the I-4 interface. This interfaceconnects individual BAN networks to UMTS networks. This interface isthus assumed to be between two legal entities, the BAN provider and theUMTS operator. One BAN network can be connected to several BSNs in oneor several operators networks, and the BSN 5 may be connected to one orseveral BAN networks provided by one or several BAN providers. Asindicated in FIG. 4, the user plane for transporting UMTS data streamsis routed directly between the access points 2 and the correspondingBSNs 5 of the two UMTS networks (cf. dash-dotted lines in FIG. 4). Tosupport accessing UMTS services via the BAN network 12, the UMTSoperator is required to install corresponding BSN nodes in the UMTSnetwork 8. When a service provisioning in a given area is agreed with aBAN provider, secure communication between the BAN gateways of the BANproviders and the BSNs of the UMTS operators must be established. Thisrequires a configuration of each others IP addresses to the networkelements, or other corresponding arrangements by means of which the BANnetwork 12 can find the address (e.g. IP address) of the BSN 5. Inaddition thereto, a configuration of a UMTS operators network code (e.g.PLMN ID) to the BAN gateway 3 and an agreement on the method andalgorithm used for authentication of control messages to be exchangedbetween the BAN gateway 3 and the BSN 5 are required. The BAN providermust ensure that similar security and connectivity is also providedwithin the BAN network 12, i.e. between the access points 2 and the BANgateway 3.

Furthermore, agreement has to be reached with regard to the services tobe provided and the billing of those. As an example, the BAN providermay bill the UMTS operator for the transport bearers used to convey UMTSdata streams between user terminals and the operators UMTS network 12for users connected to the UMTS network 8 via the BAN network 12. Toachieve this, the UMTS operator and the BAN provider should beforehandagree on what kind of access specific transport means the BAN network 12will be requested to provide for UMTS data streams towards the UMTSnetwork 8. The access points 2 in the BAN network 12 are arranged tosupport certain air interface standards with certain versions. The UMTSoperator may define mapping rules between UMTS QoS (Quality of Service)and the QoS as defined by the air interface standards (1-2 interface)that are utilized within the BAN network 12. When establishing atransport function for new UMTS data streams, these mapped parametersshould be provided to the BAN network 12 from the UMTS network 8. Inaddition to a set of possible types of transport bearers, also thebilling rules for each of those bearers should be agreed.

When a new UMTS radio bearer needs to be established, the BSN 5 in theUMTS network 8 requests to setup a suitable transport bearer from theagreed set or decides to multiplex the new UMTS radio bearer to one ofthe already existing transport bearers by UMTS specific means. If a newtransport bearer is required, the BSN 5 issues a command to the BANnetwork 12 to set up this kind of transport bearer by issuing the mappedair interface QoS parameters for the desired access specific channel tothe BAN network in a UMTS DATA STREAM SETUP (UDS SETUP) message of theANCP. The UDS SETUP message is a clear indication to the BAN network 12about the characteristics of the required BAN air interface radio link.After the bearer has been setup, both the access point 2 and the BSN 5can start collecting billing information according to the billingprinciples agreed for the established transport bearer type. The accesspoint 2 collects this billing information and sends it occasionally to abilling server provided in a BAN network 12. The BAN provider issues abill to the UMTS operator according to their agreed way of handlinginvoicing. The BAN provider is not aware of the user identities, suchthat a user specific charging is not possible and not even desired dueto user identity information confidentiality. In particular, the accesspoints 2 or another device in the BAN network 12 monitors the BANresource usage by each active connection between mobile terminals and aspecific cellular network (e.g. the UMTS network 8) via the BAN network12. This device then reports this resource usage or an accountinginformation to a centralized device in the BAN network 12 e.g. by an AAAprotocol (accounting, authentication and authorization protocol). Thiscentralized device collects the resource usage and sorts it according tothe originating cellular network. This accounting information is thenused to charge the BAN usage from each operator of the cellularnetworks.

The UMTS operator of the UMTS network 8 should collect the charginginformation of individual users or their BAN usage. This can be done asnormally in UMTS by issuing CDRs to a billing center of the UMTS network8 from the SGSN 6. The UMTS operator may as well collect information forchecking the billing of the BAN provider. This function may reside inthe BSN 5.

FIG. 5 shows a schematic diagram indicating BAN addressing andconnections. In the case shown in FIG. 5, no mobile terminal isassociated with a first access point AP 1 and two mobile terminals MT 1and MT 2 are associated with a second access point AP 2. In particular,a first mobile terminal MT 1 is utilizing two transport bearers(indicated by the solid lines) via the BAN network 12, while the secondmobile terminal MT 2 is utilizing only one transport bearer. The dottedlines indicate common BAN connection management links and the dashedlines indicate dedicated BAN connection management links. As can begathered from FIG. 5, the BAN network nodes are permanently connected toeach other with so-called common BAN connection management links(CBCML). Additionally, for every currently associated mobile terminalone dedicated BAN connection management link (DCBML) is provided betweenthe respective access point and the BAN gateway 3 as well as between theBAN gateway 3 and the BSN 5. Thus, for every transport bearerestablished between a mobile terminal and the BSN 5, one user planeconnection is established between the access point and the BSN 5.

Within the BAN network 12, every access point and BAN gateway shouldhave an IP address. The IP address used inside the BAN network 12 may bea private address. Every access point must be aware of the IP address ofthe BAN gateway to which it is connected. On the other hand, the BANgateway 3 must be aware of IP addresses of every access point connectedto it. The BAN gateway 3 and the BSN 5 must be able to address eachother by an IP address. Thus, the BSN 5 and the BAN gateway 3 arereachable at least via one public IP address known in the agent node. Incase access points have private addresses, the user plane connectionsare routed via a network address translator, which needs to becontrolled dynamically by the BAN gateway 3.

Generally, the control plane is terminated in the BAN gateway 3, whilethe user plane connections may be directly routed between the accesspoints 2 and the BSN 5. The 1-3 interface is thus a control onlyinterface connecting the access points 2 to the BAN gateway 3, and the1-4 interface is a combined user and control plane interface connectingthe BAN gateway 3 to the BSN 5.

Between each of the access points 2 and the BAN gateway 3 and betweeneach BAN gateway 3 and BSN 5 there is one semi-permanent common BANconnection management link (CBCML). The links between the access points2 and the BAN gateway 3 and the connection between the BAN gateway 3 andthe BSN 5 are independent of each other. A common BAN connectionmanagement link is established when the agent node is installed to thenetwork and is re-established at the reset of the agent node. The commoncontrol connection uses the signaling protocol transport function on topof dedicated UDP transport connections over IP. This specific CBCML isthus identified between these nodes by the source and destination IPaddresses and the source and destination UDP port numbers. Inparticular, the CBCML is used to exchange the node initializationmessages at setup or reset, and to distribute UMTS system informationand paging messages. The BAN gateway 3 is responsible for distributingsuch a system information and pagings over the I-3 interface based onprocedures executed in the I-4 interface.

For every mobile terminal having an association with one of the accesspoints 2 in the BAN network 12, a dedicated BAN connection managementlink (DBCML) is established between the access point 2 and the BANgateway 3 as well as between the BAN gateway 3 and the BSN 5. This DBCMLis similar to the common BAN connection management link but assignedspecifically to one mobile terminal. A DBCML is used to initializeitself for a new mobile terminal, to setup and release transport bearersfor UMTS data streams, and to release itself. The BAN gateway 3 isresponsible for the correct mapping between the DBCMLs of the I-3interface and the I-4 interface by performing a proper IP address andUDP port number mapping.

For every UMTS data stream conveyed via the BAN network 12, a user planeconnection is established. It is noted that one UMTS data stream cancarry information belonging to one or several UMTS radio bearers. Alldata that is exchanged between the BSN 5 and the mobile terminal 1, i.e.both UMTS user plane and UMTS control plane data, is transmitted throughthe BAN network 12 in these user plane transport bearers. As alreadymentioned, the user planed connection is directly established betweenrespective one of the access points 2 and the BSN 5, if the possiblenetwork layer equipment such as the Network Access protocol Trailer(NAT) is not taken into account.

The user plane utilizes a UDP over IP transport function and is thusidentified by the source and destination IP address at a network layerand the UDP port numbers at the transport layer identifying thisspecific user plane transport bearer. The UDP port numbers are selectedfrom the dynamic range of port numbers. In particular, user planeconnections are used to transfer individual UMTS bearer datagrams (UMTSMAC-PDUs) between the access points 2 and the BAN gateway 3 and betweenthe BAN gateway 3 and the BSN 5. Then, in the BSN 5, a transport channelis mapped to one user plane transport bearer. In the access points 2,the user plane transport bearer is mapped further to a logicalconnection over the air interface I-2 and finally the logical connectionis mapped back at the mobile terminal 1 to the UMTS transport channel.The BAN gateway 3 is responsible for network address translation andport mapping of the control plane BAN connection management links aswell as for managing the possible mapping between private and publicaddresses of the user plane transport bearers.

Separate signaling protocol connections are used for each CBCML andDBCML on the I-3 interface and the I-4 interface. The signaling protocolconnections are initialized by agent nodes, i.e. an access point in theI-3 interface and the BAN gateway 3 in the I-4 interface, when the agentnode is initialized. The first signaling protocol message, whichcontains the ANCP initialization message, is sent to the manager nodeknown IP-address with the well-known UDP port of the signaling protocolas a destination UDP port. The agent node shall utilize a free UDP portfrom the dynamic range at its source address. The agent node can alsoselect a suitable IP address as its source IP address. The manager nodereplies to the initialization message by a message containing a selectedIP address and UDP port number from the dynamic range as the sourceaddress and the indicated agents IP address and UDP source port as thedestination address. After the exchange of these messages, the selectedUDP port numbers are used in subsequent communications via theestablished signaling protocol connection. The signaling protocolconnection can be released locally after having successful exchangedANCP level release messages.

As the BSN 5 is not aware of the structure of the BAN network 12, itonly sees the BAN gateway 3. The BAN management is therefore donecompletely within the BAN network 12.

FIGS. 6A to 6C show protocol stacks of the user plane of the airinterface I-2. In particular, FIG. 6A shows the protocol stacks of theBAN user plane at the mobile terminal 1 and the access points 2. As canbe gathered from FIG. 6A, the mobile terminal 1 or user equipment (UE)comprises higher layer protocol functions (UMTS CL and Packet CL) forestablishing the direct user plane connection between the mobileterminal 1 and the BSN 5. Additionally, lower layer protocol functions(BRN DLC and BRAN L1) are provided for establishing the control planeconnection to the BAN network 12. The same applies to the protocolstacks of the access points 2.

FIG. 6B shows the protocol stacks of the UMTS Access Stratum User planebetween the mobile terminal 1 and the BSN 5. A stratum defines agrouping of protocols related to one aspect of the services provided byone or several highest-level groups of physical entities. The accessstratum is a functional grouping consisting of the parts in theinfrastructure and in the user equipment and the protocols between theseparts specific to the access technique, i.e. the way the specificphysical media between the user equipment and the infrastructure areused to carry information. The access stratum provides services relatedto the transmission of data over the radio interface and the managementof the radio interface to the other parts of the UMTS network 8. As canbe gathered from FIG. 6B, the user plane connection is directlyestablished between the mobile terminal or user equipment and the BSN 5by the air protocol layers UMTS RLC and UMTS MAC. In the lower protocollayers, the access points 2 provide an adaptation or mapping functionfor mapping the lower layers of the BRAN user plane to the UDP/IP andL2+L1 protocol functions, respectively. In the BAN gateway 3 anadditional address and port mapping is performed by the NAT so as toprovide the lower layer connection.

FIG. 6C shows the protocol stacks for the UMTS Non Access Stratum UserPlane between the mobile terminal 1 and the GGSN 7. In this case, aconnection is established via the BAN network 12, the SGSN 6 and theGGSN 7 of the UMTS network 8 to an external network such as the Internet10. The UMTS Access Stratum User Plane indicated in FIG. 6D is used toroute the call to the BSN 5. Based on the higher UMTS PDCP layer in theBSN 5, a mapping to the GPRS protocol layers GTP-u (GPRS TunnelingProtocol), lu FP (Frame Protocol) and lu transport bearer is achieved.At the SGSN 6, the lu FP layer and the lu Transport Bearer layer aremapped to the transport bearer of the external network.

FIGS. 7A to 7C show protocol stacks of the control plane of the I-2interface. As can be gathered from FIG. 7A, the mobile terminal 1 andthe access points 2 comprise an additional lower layer BRAN MAC requiredfor the media multiplexing/demultiplexing function of the control plane.

Furthermore, the UMTS Access Stratum Control Plane shown in FIG. 7Bprovides an additional higher layer UMTS RRC for the radio resourcecontrol function at the mobile terminal 1 and the BSN 5. In case of theUMTS Non Access Stratum Control Plane shown in FIG. 7C, additionalhigher layer mobility management (MM) and security management (SM) UMTSfunctions are provided in an additional higher protocol layer at themobile terminal 1 and the SGSN 6. Furthermore, the BSN 5 is arranged tomap the protocol layers of the UMTS Access Stratum Control Plane to aRadio Access Network Application Part (RANAP) layer and a lu signalingbearer required for the corresponding control signaling.

FIG. 8 shows a combined UMTS-HL2 radio interface protocol architectureas provided in the BSN 5, access points 2 and the mobile terminal 1 forthe interface function between the UMTS network 8 and the BAN network12. The Broadband Radio Access Network (BRAN) standardizing of the ETSIdenotes a number of technologies suitable for the implementation ofbroadband radio access networks. Among these technologies, onetechnology is known as HIPERLAN 2 (HL2). These wireless access networksare intended to support a variety of core networks, including thosebased on IP. The combined UMTS-HL2 radio interface protocol architecturecomprises a BRAN HL2 layer 101, a BRAN HL2 DLC layer 102, a BRAN HL2convergence layer 103, a UMTS L2/MAC layer 104, a UMTS L2/RLC layer 105,a UMTS L3 RLC layer 106 and a L2/PDCP layer 107.

Compared to the normal UMTS/UTRAN (UMTS Terrestrial Radio AccessNetwork) protocol architecture defined in the ETSI 3GPP specification TS25.323, the following differences to the UMTS parts can be defined. Inthe architecture shown in FIG. 8, only the packet switched domain issupported, i.e. all radio bearers are utilizing PDCP protocol servicesas defined in the ETSI 3GPP specification TS 25.323, “Packet DataConvergence Protocol (PDCP)”. Furthermore, only a dedicated transportchannel (DCH) of the UMTS architecture can be utilized. In additionthereto, the UMTS CCCH messages are mapped to a DCH transport channel.The UMTS paging and system information broadcast messages are nottransmitted via RLC and MAC protocols, but instead, at the network side,the information of the contents of those messages and additionallynecessary scheduling information is directly supplied by the RRCfunction 106 to the BRAN HL2 UMTS convergence layer 103 via thebroadcast control SAP (Service Access Point). In the mobile terminal 1or user equipment (UE), the system information and paging messages arereceived by the RRC function 106 directly from the BRAN HL2 UMTSconvergence layer 103 via the broadcast control SAP. In particular, theBRAN HL2 convergence layer 103 comprises a common part 1031 throughwhich a DLC User SAP signaling is routed to a U-plane 1033 of the BRANHL2 UMTS SSCS (Service Specific Convergence Sublayer). Furthermore, theDLC control SAP signaling is routed to a DC 1034 which it is directlyrouted to the UMTS L3 RRC 106. The U-plane 1033 the broadcast signalingis routed via a BC-plane 1035 to the UMTS L3 RRC 106. In contrastthereto, the TL user SAP signaling is routed from the U-plane 1033 viathe UMTS L2/MAC layer 104 to respective RLC functions 1051 of the UMTSL2/RLC layer 105. Then, the logical channels are either routed to theUMTS L3 RRC function 106 or to respective PDCP functions 1071 of theL2/PDCP layer 107, based on the multiplexing/demultiplexing functionprovided at the MAC layer 104 for separating/combining the control anduser plane signaling. The UMTS SSCS layer 1032 resides on top of thecommon part 1031 and the DLC layer 102. It provides a means of using andpreserving the UMTS MAC frame over the I-2 radio interface of the BANnetwork 12. It also manages UMTS broad-cast data over the radiointerface, e.g. system information and paging messages. In the interfacebetween the higher layers and the UMTS SSCS 1032, UMTS control and userdata are transferred as UMTS data streams. In the UMTS SSCS 1032, eachUMTS data stream is mapped to a different HL2 DLC User Connection (DUC)of the BAN network 12. Therefore, the DUC IDs used in the BAN network 12are mapped to UMTS data stream IDs. Additionally, connection controlbetween the access points 2 and the mobile terminal 1 are performed inthe UMTS SSCS 1032 according to requests from the higher layers of themobile terminal 1 or external networks. In the connection controlprocess, a HL2 MAC ID is mapped to a UMTS connection ID. Setup andrelease of UMTS data streams is also performed in the UMTS SSCS 1032.

The broadcast procedure of UMTS broadcast data is performed in therespective UMTS SSCS function of the access points 2. The UMTS broadcastdata are received from external networks and converted to a UMTS datastream in the UMTS SSCS according to their scheduling informationreceived from the external networks. The UMTS data stream is thenbroadcast over the 12 interface. The UMTS SSCS 1032 is also responsiblefor mapping UMTS system frames to HL2 frames of the BAN network 12.

To perform all UMTS SSCS functions, the UMTS SSCS 1032 is subdividedinto the U-Plane (User plane) 1033, the BC-Plane (Broadcast Controlplane) 1035 and the DC-Plane (Dedicated Control plane) 1034. It is to benoted that the Common Part 1031 is transparent to the DC-Plane 1034. Theprocedures of the U-Plane 1033 provide the capability to transfer UMTSSSCS SDUs (Service Data Units) between the UMTS SSCS of the accesspoints 2 and one or more UMTS SSCSs of mobile terminals associated withthe access points 2 over the BAN network 12. To achieve this, theU-Plane 1033 comprises a transfer function for transferring UMTS controland user data from/to the higher layers and the BC-Plane 1035 andfrom/to the lower layers, and mapping functions for mapping UMTSconnections and UMTS data streams of the higher layers to the HL2connections and HL2 DLC connections, respectively, of the lower layersbased in their respective IDs. The BC-Plane 1035 handles UMTS broadcastdata based on asymmetric procedures which differ in the mobile terminal1 and in the access points 2 due to their broadcast receiving andtransmitting nature, respectively.

Finally, the DC-Plane 1034 is responsible for the establishment,management and release of UMTS data streams. This comprises indicationof UMTS SSCS initialization and triggering of UMTS CL broadcast join,UMTS connection setup, UMTS connection release, UMTS data stream setupand UMTS data stream release procedures.

FIG. 9 shows protocol stacks for the I-3 interface between the accesspoints 2 and the BAN gateway 3. In both network elements, the protocollayers comprise an ANCP layer on top of a signaling protocol layer (e.g.SMNP as indicated in FIG. 9) on top of an UDP/IP layer on top of L2+L1layers.

Similarly, as indicated in FIG. 10, the protocol stack of the I-4interface between the BAN gateway 3 and the BSN 5, comprises the ANCPlayer on top of the signaling protocol layer (e.g. SNMP as indicated inFIG. 10) on top of the UDP/IP layer on top of the L2+L1 layer.

FIG. 11 shows a signaling diagram for an initialization of an accesspoint 2 towards the BAN gateway 3, wherein an installed or reset accesspoint is connected to the BAN gateway 3. This signaling example showsthe required signaling when a new AP is installed to the BAN network 12or an existing AP has to be reset. The access point has a securityassociation with the connected BAN gateway 3. Thus, security associationinformation is assumed to be pre-configured in the access point.

Upon setup and reset, every access point shall establish a common BANConnection Management Link to its designated BAN gateway. This signalingconnection operates on top of the signaling protocol on top of theUDP/IP transport protocol.

The access point establishes the connection by sending an ANCPINITIALIZATION message to the BAN gateway 3.

The INITIALIZATION message may contain e.g. a list of the supportedaccess specific air interface protocol versions, a list of supportedANCP versions, and an AP node identifier. Reception of INITALIZATION isacknowledged by the BAN gateway 3 with an INITIALIZATION ACK messagecontaining an ID of the selected ANCP protocol version and a BAN gatewaynode Identifier.

The exchange of these two messages initializes the Common BAN ConnectionManagement Link (CBCML) between the access point and the BAN gateway.The transport addresses for the CBCML are allocated during theinitialization procedure by setting the source IP address and source UDPport ID to desired values for the CBCML both in the INITIALIZATION andINITIALIZATION ACK messages.

In addition to the indication of the reset, the Common BAN ConnectionManagement Link (CBCML) will be used to distribute UMTS broadcastinformation and paging messages to the access points 2 from the BANgateway 3.

FIG. 12 shows a signaling diagram for an initialization of the BANgateway 3 towards the BSN 5. This signaling example shows how the BANgateway 3 is connected to the BSN 5. One BAN gateway may be connected toseveral BSNs of the same operator as well as to BSNs in severaloperators networks.

Similarly to the access points 2, every BAN gateway has a securityassociation with the UMTS operator BSNs to which it is connected.Security association is assumed to be created manually.

Upon setup and reset, the BAN gateway 3 establishes a Common BANConnection Management Link with its designated BSNs. The setup isperformed similarly as in the procedure of AP initialization describedin connection with FIG. 11.

FIG. 13 shows a signaling diagram for a UMTS information broadcastingover the BAN network 12. UMTS Information Broadcasting is used tobroadcast UMTS specific information over the access specific I-2 radiointerface. UMTS information consists of UMTS System Information andPaging messages.

This signaling sequence consists of two parts, a system informationdistribution to and within BAN network 20 and a system informationbroadcasting over the air. The distribution of system information withinthe network utilizes the established Common BAN Connection ManagementLink (CBCML).

The BSN 5 and the BAN gateway 3 are responsible for the systeminformation distribution towards the access points 2. The BSN 5 sendsthe UMTS system information to the BAN gateway 3 which then distributesthe information towards all connected access points. The BAN gateway 3may receive system information from a plurality of BSNs from differentUMTS or other cellular networks.

The access point is then responsible for periodical UMTS systeminformation broadcasting over the broadband air interface I-2 asspecified in the access specific UMTS Convergence layers.

FIG. 14 shows a state transition diagram of the mobile terminal 1according to the preferred embodiment. The mobile terminal 1 can be inthree states: NULL, IDLE and CONNECTED. These states describe the stateof the connection between the mobile station 1 and the UMTS network 8,and not the state of UMTS protocols.

In the NULL state, the mobile station 1 does not hear the UMTS broadcastinformation and thus can not know the existence of UMTS coverage and cannot connect to UMTS networks. The mobile station 1 transits to the IDLEmode (see arrow A in FIG. 14) when it is switched on and startslistening to UMTS broadcast information from the subscribed UMTSnetwork. The mobile station 1 enters this state either after havingfound the UMTS Broadcast signal by searching the access specificfrequencies or by asking the UMTS broadcast channel information fromclosest access point.

When the mobile terminal 1 needs to contact the UMTS network 8, ittransits to the CONNECTED state (see arrow B). This state is enteredafter the mobile terminal 1 has an association with the closest accesspoint, has told the subscribed PLMN-ID to the access point and after theBAN network 12 has set messages with the UMTS network 8 by utilizingdedicated transport channels associated to the set up transport bearers.

The mobile terminal 1 enters to IDLE state from CONNECTED state (seearrow C), when the last transport bearer for UMTS data is released andthe mobile terminal 1 has been disassociated from the access point. Notethat the UMTS connection might still logically exist between the mobileterminal 1 and the UMTS network 8, e.g. in the RRC state URA-Connected.

The mobile terminal 1 enters back to the NULL state (see arrow D) whenit is not able to receive any UMTS broadcast information. This might bedue to moving away from the coverage of the BAN network 12 or due toswitching the power off.

FIG. 15 shows a signaling diagram for a network assisted statetransition from the NULL state to the IDLE state. This state transitioncan occur without any signaling if the mobile terminal 1 is capable ofreceiving or finding UMTS System Information broadcasted by theassociated access point itself. This is possible since from all accesspoints within one access network the UMTS broadcast should betransmitted in the same channel, or if the mobile terminal 1 findsitself the UMTS broadcast stream by scanning the access frequencies.

If the mobile terminal 1 is not capable of finding itself the UMTSBroadcast information from the closest access point supportingconnectivity to UMTS network 8, the following signaling should beexecuted to request the BAN network 12 to indicate the location of theUMTS broadcast information of the subscribed UMTS network 8.

In general, the mobile terminal 1 establishes a communication or datatransfer means between itself and a selected one of the access points 2.Then, the mobile terminal 1 asks for information about the availabilityor location of a cellular broadcast network information. In particular,the mobile terminal 1 may indicate to the selected access point anindicator (e.g. PLMN-ID) indicating the cellular network from which thebroadcast data is desired to be received. In response thereto, the BANnetwork 12 indicates to the mobile terminal 1 the address or similarlocation information about a cellular network broadcast signal. In casethe mobile terminal 1 has indicated the desired cellular network, theBAN network 12 may indicate a pointer to the broadcast informationspecifically from the desired cellular network. If the communicationmeans is no longer required, it may be released.

In the following, the above general procedure is described in moredetail with reference to FIG. 15 for the case of the BRAN HL2 protocolsignaling. The mobile terminal 1 initiates the state transition byassociating with the closest access point. The set up of access specificencryption or authentication is not necessary. After negotiating theaccess specific link capabilities, the mobile terminal 1 asks for thelocation of UMTS broadcast information by sending UMTS_BROADCAST_JOINRLC message to the access point. This message indicates the PLMN-ID ofthe UMTS network 8 the broadcast information of which is desired to bereceived.

The access point responds with a UMTS_BROADCAST_JOIN_ACK messagecontaining the MAC-ID and the scheduling information broadcastinformation of the subscribed network, e.g. the UMTS network 8.

After this signaling procedure, the mobile terminal 1 is able to findthe UMTS Broadcast information from the pointed location and theassociation with the access point can be removed, since there is no needto establish a connection to the UMTS network 8.

FIG. 16 shows a signaling diagram for a transition from IDLE state toCONNECTED state. This state transition occurs when the mobile terminal 1needs to contact the UMTS network 8. This can happen e.g. if the mobileterminal 1 receives a paging message or if the mobile terminal 1 needsto contact the UMTS network 8 due to mobile originated reasons.

In general, the mobile terminal 1 establishes a communication or datatransfer means between itself and a selected one of the access points 2.Then, the mobile terminal 1 indicates to the BAN network 12 a cellularnetwork (e.g. the UMTS network 8) towards which a connection is desired.In particular, the mobile terminal 1 may add some cellular networkspecific information to the respective message. In response thereto, theBAN network 12 indicates to the indicated cellular network the existenceof a new mobile terminal desiring to communicate with the cellularnetwork. If a network specific information was received from the mobileterminal 1, it is forwarded to the cellular network in this indicationor message. Thereafter, the desired cellular network initiatesestablishment of a communication or data transfer means between itselfand the mobile terminal 1 by requesting or indicating a setup of atransport bearer between itself and the BAN network 12. The desiredcellular network may include BAN specific parameters to facilitate theselection of a proper access channel by the BAN network 12 for thisconnection between the mobile terminal 1 and the desired cellularnetwork. Additionally, the desired cellular network may add a cellularnetwork specific information to this message. The BAN network 12 thenestablishes access specific communication or data transfer means betweenitself and the mobile terminal 1, and prepares means to map theestablished transport bearer to the established access specificcommunication means. If a cellular network specific information wasreceived from the desired cellular network, it is passed on to themobile terminal 1 during the establishment of the access specificcommunication means. Finally, the BAN network 12 completes theestablishment of the communication means by indicating the completion ofthe establishment of the access channel to the mobile terminal 1 and thecompletion of the establishment of the transport bearer to the desiredcellular network. In the following, the above general procedure isdescribed in more detail with reference to FIG. 16 for the case of theBRAN HL2 protocol signaling. The mobile terminal 1 initiates the statetransition by associating with the closest access point. Afterassociation, mobile terminal 1 sends an RLC_INFO message to the accesspoint. This message indicates the PLMN-ID of the UMTS network towardswhich the connection shall be established.

The access point sends a CONNECTION SETUP message towards the indicatednetwork. The pre-configured transport address for the indicated PLMN-IDis used for this purpose. When the BSN 5 receives the CONNECTION SETUPmessage, it initializes the establishment of a first transport bearerfor the UMTS data streams. This transport bearer will carry at least theinitial UMTS signaling bearers between the mobile terminal 1 and the BSN5.

The BSN 5 initializes the transport bearer setup by sending a UMTS DATASTREAM SETUP message towards the transport address indicated as a sourceaddress in the CONNECTION SETUP message. The UDS DATA STREAM messagecontains e.g. the ID for the UDS to be established, the access specificQoS parameters for the air interface link for this UDS, the desireddestination transport address for UDS datagrams to be sent towards theBSN 5 from BAN network 12, the binding information to be passed to themobile terminal 1 together with the access specific air interfacechannel establishment.

The access point sets up the access specific link towards the mobileterminal 1 utilizing the indicated. QoS parameters. After successfulestablishment of the link, the access point responds towards the BSN 5with a UDS SETUP COMPLETE message containing the desired destinationtransport address for the UDS datagrams to be sent towards the accesspoint from the UMTS network 8.

After this signaling procedure, an exchange of UMTS messages via thetransport channels mapped to the established transport bearers ispossible. The mobile terminal 1 knows the allowed transport channels andtheir mapping to the established transport bearer from the Bindinginformation passed to the mobile terminal 1 together with theestablishment of the transport bearer.

FIG. 17 shows a signaling diagram for a transition from the NULL stateto the IDLE state and directly to the CONNECTED state. This signalingsequence is utilized when the mobile terminal 1 desires to establish aconnection to the UMTS network 8, but is not able to find itself thenecessary UMTS broadcast information. In this situation the mobileterminal 1 needs to first ask the network to point out the location ofthe UMTS broadcast information and then, when transition to the IDLEstate is completed, directly transit to the CONNECTED state byestablishing a connection to the UMTS network.

This state transition sequence begins similarly as the normal transitionfrom the NULL state to the IDLE state with network assistance. When theUMTS broadcast information is found, the mobile terminal 1 in this casedoesn't release the association with the access point but requests theaccess point to connect the mobile terminal 1 to the UMTS network 8 byissuing an RLC INFO message. This message contains the subscribedPLMN-ID.

After this phase, the signaling is similar as in the transition from theIDLE state to the CONNECTED state shown in FIG. 16. Therefore, thefurther description is omitted.

FIG. 18 shows a signaling diagram for a transition from the CONNECTEDstate to the IDLE state. This transition occurs when the physicalconnection between the UMST network 8 and the mobile terminal 1 isreleased. Note that the logical connection realized by the UMTS RRCprotocol may continue to exist e.g. in RRC state URA connected.

In the normal case, this state transition is initiated by the BSN 5 whenthere is no need to further maintain the physical connection to themobile terminal 1. This can happen e.g. when the RRC connection isreleased, after handover to another access point or to another radiosystem or e.g. when the RRC state changes to URA connected. Theconnection release may also be triggered due to a radio interfacecongestion of the BAN network 12 or due to a loss of the radioconnection to the BAN network 12. In this case a BAN node (either theaccess point or the BAN gateway 3) starts the signaling sequence bysending a CONNECTION RELEASE REQUEST message towards the BSN 5, afterwhich the BSN 5 initiates the connection release as described below.

The BSN 5 initiates the state transition by issuing a CONNECTION RELEASEmessage. When the access point receives this message, it disassociatesthe mobile terminal 1 and releases all information related to thereleased connection. The mobile terminal 1 also releases all informationrelated to the previously allocated transport bearers. The access pointresponds towards the BSN 5 with a CONNECTION RELEASE COMPLETE message.

FIG. 19 shows a signaling diagram for a UMTS data stream setupoperation. This signaling sequence is initiated by the BSN 5 if atransport bearer for a new UMTS data stream needs to be established tocarry UMTS radio bearers. Note that several UMTS radio bearers can bemultiplexed by the UMTS MAC protocol within one transport bearer andthus a new transport bearer is not usually required for every new UMTSradio bearer.

In general, the concerned cellular network (e.g. UMTS network 8) and themobile terminal 1 may exchange a cellular network specific signalingrequired to set up new data streams between themselves. The cellularnetwork initiates establishment of a communication or data transfermeans between itself and the mobile terminal 1 by requesting/indicatinga setup of a transport bearer between itself and the BAN network 12. Thecellular network may add BAN specific parameters to facilitate theselection of a proper access channel by the BAN network 12 for thisconnection between the mobile terminal 1 and the cellular network. Thecellular network may also add a cellular network specific information tothis message. The BAN network 12 then establishes access specificcommunication means between itself and the mobile terminal 1 andprepares means to map the established transport bearer to theestablished access specific communication means. If a cellular networkspecific information was received from the cellular network, it ispassed on to the mobile terminal 1 during the establishment of theaccess specific communication means. Thereafter, the BAN network 12completes the establishment of the communication means by indicating thecompletion of the establishment of the access channel to the mobileterminal 1 and the completion of the establishment of the transportbearer to the cellular network. The cellular network and the mobileterminal 1 may then exchange a cellular network specific signaling toset up new data streams between themselves.

In the following, the above general procedure is described in moredetail with reference to FIG. 19 for the case of the BRAN HL2 protocolsignaling. Initially, an RRC RADIO BEARER SETUP message (or other RRCmessage having similar radio bearer setup function) is sent to themobile terminal 1, and an ANCP UDS SETUP message is sent to the BANgateway 3. The BAN gateway 3 then initiates a corresponding UDS setuptowards the access point. The UDS SETUP message contains e.g. the ID forthe UDS to be established, the access specific QoS parameters for theair interface link for this UDS, the desired destination transportaddress for UDS datagrams to be sent towards the BSN 5 from BAN network12, the binding information to be passed to the mobile terminal 1together with the access specific air interface channel establishment

The access point sets up the access specific link towards the mobileterminal 1 utilizing the indicated QoS parameters. After successfulestablishment of the link, the access point responds towards the BSN 5with a UDS SETUP COMPLETE message containing the desired destinationtransport address for the UDS datagrams to be sent towards the accesspoint from the UMTS network 8.

After this signaling procedure, the exchange of UMTS messages via thetransport channels mapped to the established transport bearers ispossible. The mobile terminal 1 knows the allowed transport channels andtheir mapping to the established transport bearer from the Bindinginformation passed to the mobile terminal 1 together with theestablishment transport bearer. FIG. 20 shows a signaling diagram forUMTS data stream release operation. This signaling sequence is used torelease one or several user plane transport bearers. The release of aspecific UDS is normally initiated by the BSN 5 and is used to releaseone or several user plane transport bearers. It is also possible thatthe BAN network 12 triggers the release of individual UDSs e.g. due tocongestion in the air interface or in the network or due to the loss ofa radio connection related to the specific UDS. In such a case, a BANnode (access point or BAN gateway) sends an UDS RELEASE REQUEST messagetowards the BSN 5.

The release is initiated by the BSN 5 by sending an UDS RELEASE message.This message contains the list of UDSs to be released. When the accesspoint receives the message, it releases the related air interface linksto the mobile terminal 1. When the air interface links are released theaccess point acknowledges the completion of the operation towards theBSN 5 by sending a UDS RELEASE COMPLETE message.

FIG. 21 shows a signaling diagram for a handover operation betweendifferent access points.

In general, the mobile terminal 1 communicates with the BAN network 12via a first one of the access points 2. The mobile terminal 1initializes the establishment of a connection to the cellular network(e.g. the UMTS network 8) via a second one of the access points 2. Then,the connection is established between the cellular network and themobile terminal 1 via the second access point. The mobile terminal 1indicates its identity and its new point of attachment to the cellularnetwork by transmitting a cellular network specific message from themobile terminal 1 to the cellular network via the second access point.In response thereto, the cellular network takes the necessary steps toreroute the connection, which was previously routed via the first accesspoint, now via the second access point.

Thus, handover is realized by just abandoning the old access point,associating with a new access point and by indicating the new point ofconnection to the cellular network (e.g. the BSN 5 of the UMTS network8) via the new access point. The BSN 5 then redirects all the existingtransport bearers towards the new access point. From the point of viewof the BAN network 12, this procedure is seen as a new connectionestablishment and from the point of view of UMTS network 8, this is seenas a re-establishment of the old UMTS RRC connection.

Thus, the BAN network 12 does not handle any handover. From the BANnetwork point of view there is no handover in the system. The handoveris realized by the mobile terminal 1 in such a manner that duringcommunication it preferably scans the signal strength of other accesspoints or access devices and preferably reads the cellular networkbroadcast information from strong candidate access devices. Then, itjust abandons the old access device and starts a normal connectionestablishment procedure towards a selected new access device. The newconnection via the new access device is set up in a normal manner andwhen the connection between the mobile terminal 1 and the cellularnetwork exists, the mobile terminal 1 signals a message indicating thatit has changed its point of attachment to the cellular network to be viathe new access device.

In the following, the above general procedure is described in moredetail with reference to FIG. 21 for the case of the BRAN HL2 protocolsignaling. When the mobile terminal 1 detects that a stronger accesspoint than the current one would be available, it initiates a handoverprocedure. To achieve this, the mobile terminal 1 first abandons theconnection towards the old access point. At this phase, also the userplane connection between the mobile terminal 1 and the UMTS network 8 isbroken.

The mobile terminal 1 establishes an association with the new accesspoint. The establishment of the association is executed exactly as for anew UMTS signaling connection. When the UMTS connection between themobile terminal 1 and the BSN 5 is setup, the BSN 5 automaticallyinitializes the setup of the first transport bearer for the associatedmobile terminal 1 also similarly as in UMTS Signaling Connection Setupprocedure.

When the first transport bearer is established, the mobile terminal 1transmits, transparently to the BAN network 12, a UMTS UTRAN RRCConnection Re-establishment Request message to the BSN 5. The BSN 5recognizes or identifies the mobile terminal 1 from the received RRCmessage. The RRC message can also be authenticated by the BSN 5 due tothe existence of the integrity protection in the message. Aftersuccessfully detecting the identity of the mobile terminal 1, the BSN 5switches the broken data flow from the old access point towards the newaccess point. If more than one transport bearer existed for the mobileterminal 1 via the old access point, then similar transport bearers aresetup also towards the new access point. Also if the new access point isconnected to a different BSN than the old access point (or if thehandover is being made from another radio system), then an SRNSrelocation as defined in UMTD is executed between the old and the newBSN.

After this, an RRC message RRC Connection Re-establishment is returnedto the mobile terminal 1, which is acknowledged by an RRC Connectionre-establishment Complete message. These messages are transparent to theBAN network 12.

It is to be noted that then execution of SRNS Relocation (via standardlu and lur interfaces) enables inter BSN, UTRAN to BAN and GERAN to BANhandovers. Normal UTRAN and GERAN inter system handovers are used forBAN to UTRAN and BAN to GERAN handovers.

In summary, the present invention relates to a method and system forproviding access to a cellular network, wherein a terminal device isconnected to an access device according to access specifications of abroadband access network which is not specifically designed to be usedas a part of cellular network. The terminal device indicates to theaccess device that it wishes to be connected to the cellular network,and a session or call and a radio bearer is setup between the terminaldevice and the cellular network. To achieve this, a service nodeprovided in the cellular network requests a suitable access bearer fromthe access network and the access device sets up a corresponding accesschannel towards the terminal device. The terminal device then associatesthe access channel to the correct radio bearer by using a correspondingidentification. Thereby, service functions of the cellular network, e.g.UMTS services, can be distributed via any access network and existingbroadband or high-speed access networks can be implemented in newcellular network structures. A huge capacity enhancement can thus beoffered to the network operators of the cellular network without anystandardization effort or license fee and at very small investment andmaintenance costs.

The present invention can be applied to any access system where aterminal device is to be connected to a cellular network via a accessnetwork. The description of the preferred embodiment is only intended toillustrate the present invention. The preferred embodiment may thus bemodified within the scope of the attached claims.

1. A system for providing access to a cellular network, said systemcomprising: a) at least one access device for establishing a connectionto said cellular network via an access network which is not specificallydesigned to be used as a part of said cellular network; and b) a servicenode specifically designed to be used as a part of said cellular networkand arranged to request an access bearer from said access network inresponse to a setup request received from said at least one accessdevice.
 2. A system according to claim 1, wherein said connection isestablished to a terminal device arranged to connect said at least oneaccess device according to the access specifications of said accessnetwork.
 3. A system according to claim 1 I, wherein said access networkis a radio access network or a broadband radio access network, operatingin a non-licensed frequency band.
 4. A system according to claim 2,wherein said terminal device is arranged to indicate a connectionrequest to said at least one access device by using an adaptation layersignaling of said cellular network, said adaptation layer signalingbeing adapted to provide a mapping functionality between the lower layerprotocols of said access network and the higher layer protocols of saidcellular network.
 5. A system according to claim 4, wherein saidadaptation layer signaling is a UMTS conversion layer signaling.
 6. Asystem according to claim 2, wherein said terminal device and saidcellular network are arranged to set up a session or call and a radiobearer.
 7. A system according to claim 6, wherein said session or callis set up by an SM or SIP signaling, and said radio bearer is set up byan RRC signaling.
 8. A system according to claim 1, wherein said servicenode is a broadband service node arranged to request said access bearerby initiating a bearer setup procedure according to a signaling protocolspecified between said access network and the cellular network.
 9. Asystem according to claim 2, wherein said terminal device is arranged toassociate an access channel set up by said access device to a correcttransport channel or other similar cellular network resource of saidcellular network by using a transport channel or similar cellularresource identification.
 10. A system according to claim 1, wherein saidaccess bearer is selected from an agreed set.
 11. A system according toclaim 1, wherein a UDP transport means is set up between said accessdevice and said service node.
 12. A system according to claim 11,wherein said at least one access device or another network device ofsaid access network is arranged to monitor resource usage by an activeconnection between a terminal device and a cellular network and toreport the monitoring result to a centralized network device which isarranged to sort the resource usage according the originating cellularnetwork and to increase an access resource charging bill for theoperator of said originating cellular network according to predeterminedrules agreed for the setup access bearer type, and to allocate acorresponding capacity for the data transmission.
 13. A system accordingto claim 11, wherein said service node is arranged to distribute abroadcast information of said cellular network to said centralizednetwork device, and said centralized network device is arranged todistribute said broadcast information to connected access devices.
 14. Asystem according to claim 1, wherein said service node providespredetermined functions of the cellular network, comprising radio bearermanagement, encryption, IP-header compression, RLC level segmentationand/or retransmission, and MAC multiplexing.
 15. A system according toclaim 1, wherein said service node is split into separate user planegateway and control plane servers.
 16. A system according to claim 1,wherein said service node is connected to an SGSN by a standard luinterface and/or to other service or switching nodes by an lur signalinginterface for supporting seamless interservice node and interaccesssystem handovers.
 17. A system according to claim 1, wherein said accessnetwork is a network arranged separately from the communication systemon which said cellular network is based.
 18. A system according to claim1, wherein said access network is arranged to be used for accessingseveral ones of said cellular network.
 19. A system according to claim18, wherein said cellular network is a UMTS infrastructure network. 20.A system according to claim 1, wherein said access network is arrangedto use bluetooth, IEEE 802.11 a/b, IEEE 802.15, or BRAN HL2 based radiotechnology.
 21. A system according to claim 1, wherein said accessnetwork is arranged to be used for establishing a connection to othertypes of networks which differ from said cellular network.
 22. A systemaccording to claim 1, wherein said access network is arranged to providealternative methods specific to said access network so as to realizelower layer protocol function of integrated access networks specificallydesigned to be used as a part of said cellular network.
 23. A systemaccording to claim 1, wherein said access network is a multipurposeaccess network adapted to offer transport services for said cellularnetwork, and said cellular network is an access independent networkadapted to be able to utilize transport services provided by severaltypes of access networks.
 24. A system according to claim 2, whereinsaid terminal device is arranged to scan the signal strength of otheraccess devices and to perform handover by starting a normal connectionestablishment procedure towards a new access device.
 25. A systemaccording to claim 1, wherein transport channel data streams to saidcellular network are transported on top of transport bearers betweensaid access network and said cellular network and on top of thecommunication channels provided by the access technology of said accessnetwork between a terminal device and the access network.
 26. A systemaccording to claim 1, wherein only dedicated transport channels of saidcellular network are used in integrated system parts specificallydesigned to be used as a part of said cellular network, when aconnection is established via said access network.
 27. A systemaccording to claim 1, wherein said access network is arranged to mapdedicated transport channel data streams of said cellular network to thecommunication channels provided by the access network.
 28. A systemaccording to claim 1, wherein said cellular network is arranged to map adesired service quality to the communication channel characteristics ofthe access network, and to use the mapped communication channelcharacteristics to request a transport service form the access networkfor a data stream to be established.
 29. A system according to claim 1,wherein said access device uses an indicated scheduling information anddefined mapping rules between time references and its internal clock forscheduling broadcast messages of said cellular network.
 30. A method ofproviding access to a cellular network, said method comprising the stepsof: a) establishing communication means between a terminal device and annon-integrated access network which is not specifically designed to beused as a part of said cellular network; b) indicating by said terminaldevice to said access network that a connection to said cellular networkis required; c) sending a request for connection setup form said nonintegrated access network to said cellular network; d) establishing adata transfer means between said access network and said cellularnetwork; e) indicating to said terminal device that a communication withsaid cellular network is enabled and optionally modifying thecommunication means between said terminal device and said non integratedaccess network based on an information received from said cellularnetwork; and f) using said established data transfer means forexchanging a signaling between said terminal device and said cellularnetwork.
 31. A method according to claim 30, wherein an associationbetween a particular data stream of said cellular network between saidterminal device and said cellular network and a particular communicationchannel between said terminal device and said access network is achievedby transferring a binding information both directly from said cellularnetwork to said terminal device and from said cellular network via saidaccess network to said terminal device upon setting up said data streamand communication channel, respectively.
 32. A method according to claim30, wherein a signaling specific to said cellular network is carried outvia said setup bearer transparently through said access network which isarranged to only allocate the respective capacity.
 33. A methodaccording to claim 30, wherein broadcasting and paging channels aremultiplexed to one access specific channel.
 34. A method according toclaim 30, wherein a broadcasting channel with the same address orlogical location is used for a group of access devices of said accessnetwork, and wherein said terminal device is arranged to listen to onlyone channel while changing between access devices of the same group. 35.A method according to claim 30, wherein a set of lower layer functionsto said cellular network is disabled and the corresponding functions ofthe access network are used instead, when said connection is set up. 36.A method according to claim 30, wherein the identify utilized by thecellular network for the user of said terminal device and/or for saidterminal device itself is not notified to said access network.
 37. Amethod according to claim 30, wherein a timing reference of theinfrastructure of said cellular network is mapped to specific timingreferences of said access network.
 38. A method according to claim 37,wherein said timing reference of said cellular network is an SFN.
 39. Amethod according to claim 30, wherein a broadcast channel of said accessnetwork is adapted to broadcast broadcast information originating fromsaid cellular network.
 40. A method according to claim 39, wherein thescheduling of said broadcast information of said cellular network bysaid access network is compatible to the scheduling of said broadcastinformation of said cellular network by an integrated access network.41. A method according to claim 39, wherein said access network receivesfrom said cellular network messages to be broadcasted together with ascheduling information used for broadcasting.
 42. A method according toclaim 41, wherein said scheduling information indicates time referencesof said cellular network at which the broadcast message shall be sent bythe access network.
 43. A terminal device for providing an access to acellular network, said terminal device comprising: a) higher layerprotocol means for providing a signaling function to said cellularnetwork; b) lower layer protocol means for providing a signalingfunction to an access network which is not specifically designed to beused as a part of said cellular network; and c) adaptation means forproviding an adaptation between said lower layer protocol means and saidhigher layer protocol means so as to establish a transparent connectionto said cellular network through said access network.
 44. A terminaldevice according to claim 43, wherein said higher layer protocolfunctions of said cellular network, and said lower layer protocol meansprovides lower layer protocol functions specific to said access network.45. A terminal device according to claim 43, wherein said higher layerprotocol functions are based on UMTS protocol functions that operate ontop of the UMTS transport channels in the UMTS protocol architecture.46. A terminal device according to claim 43, wherein said terminaldevice is arranged to establish a new connection with said accessnetwork, which is not associated to a previous connection by said accessnetwork, when said terminal device moves from the coverage of one accessdevice to the coverage of another access device of said access network.47. A terminal device according to claim 43, wherein said terminaldevice is arranged to inform only an identifier of said cellular networkto said access network, when said terminal device contacts said accessnetwork for accessing said cellular network.
 48. A terminal deviceaccording to claim 43, wherein said terminal device is arranged to useits power saving features specific to said cellular network whenmonitoring a broadcast information of said cellular network via saidaccess network, by determining compatible transmission times for piecesof broadcast system information of said cellular network and byactivating its receiver functions only at required time instances.
 49. Anetwork node for providing access to a cellular network, said networknode comprising: a) higher layer protocol means for communicating with aterminal device via an access network which is not specifically designedto be used as a part of said cellular network; and b) lower layerprotocol means for signaling with said access network to request asuitable access bearer from said access network; c) wherein saidsuitable access bearer is used to establish a transparent connectionbetween said terminal device and said network node through said accessnetwork.
 50. A network node according to claim 49, wherein said networknode is a broadband service node, and said access network is a broadbandradio access network.
 51. An access device for providing access to acellular network, said access device comprising: a) higher layerprotocol means specific to said cellular network, for receiving from aterminal device a signaling indicating a request for a connection tosaid cellular network; and b) lower layer protocol means specific to anaccess network which is not specifically designed to be used as a partof said cellular network, said lower layer protocol means being arrangedto handle the setup of a connection to a service node of said cellularnetwork via said access network in response to the receipt of thesignaling and to setup a requested type of access channel towards saidterminal device, which has been requested by said service node.
 52. Anaccess device according to claim 51, wherein said access device is anaccess point, and said access network is a broadband radio accessnetwork.